One company I work for has a building diagramming program. You can diagram a building OK on Windows 7, it just won't let you label the individual areas of the building. Works fine on XP and XP Pro. The techies are stumped.
Then, too, on downloading, editing, and resizing photos, it seems everything that takes one step on XP takes two or three steps on Windows 7. It seemed like when I tried to run 7, I wound up spending a LOT more time on the computer. And since I get paid by the job and not by the hour, I went back to XP just to get my work done efficiently again.